2012 Buick LaCrosse with eAssist

Reality: Much-improved mileage over the standard four-cylinder LaCrosse, no noticeable sacrifice in performance, and everything worked well. And, yeah, it's kind of pretty.

Not a hybrid: The eAssist system in the LaCrosse adds a small electric motor, regenerative braking, and a lithium-ion battery. It allows the vehicle to store enough power to run accessories while the engine shuts down at stoplights, and cuts fuel when braking. (Engineers also worked to reduce curb weight, and borrowed grilles that shut at highways speeds from the Chevrolet Cruze Eco.)

The system is also available on the Buick Regal and will be offered in the LaCrosse's cousin, the 2013 Chevrolet Malibu, in the spring (read about my test of the Malibu here: www.philly.com/driversseat).

First, its thirst: In a mix of city and highway driving, I averaged 30 m.p.g., which is exactly 25 percent better than the 24 I got from the 2011 LaCrosse four-cylinder I tested in April.

Big warranty: If you're like me and tend to worry about fancy-schmancy new gadgetry down the road, General Motors offers a little peace of mind. Its eAssist components come with an eight-year, 100,000-mile warranty.

Living with eAssist: The system is fairly smooth. The average driver might not notice any difference between it and a regular version of the LaCrosse.

But being better than the average driver - or certainly more faultfinding - I notice it does have a slight gasp when switching back on from auto-stop mode at a red light. Still, I found simply taking my foot off the brake a second before I planned to move cured this completely.

On the road: The handling is sure and smooth. It's certainly not sporty, but it's not fluffy either.

Inside: The interior itself is as pretty as the four-cylinder 2011 model I tested last year. The seats are luxurious but supportive, the dashboard is attractive, and the vehicle is roomy.

Outside: The design falls a little flat. Last year's red LaCrosse looked lively. This year's beige model - identical in design - would work well in the geriatrician's parking lot.

Entertain me: The stereo is a little button-heavy and can be difficult to follow. But the display is attractive enough.

The special entertainment package ($600) gives you 384 watts vented through 11 speakers, and the resulting sound is superb. For an additional $1,345, you get navigation and backup camera. The raked rear window makes the latter feature worth its price.

Night shift: An accent-lighting strip across the dash and gauges dressed in blue and white makes this a pretty evening companion. Overhead lights are focused and don't interfere with the rearview mirror.

Hold my calls: Perhaps by design, the only good spot for a cellphone is a drawer to the left of the steering wheel. It's good if you're trying to stay off the phone while driving. But it becomes easy to forget Mr. Phone when the driving is done.

Where it's built: Kansas City, Kan.

How it's built: J.D. Power puts the predicted reliability for the 2011 model at "better than most." And Buick has received high marks for quality over the last several years.

In the end: The LaCrosse with eAssist definitely is worth a consider for large sedan buyers.

But it is worth noting that a Volkswagen Passat offers just as much room in an even nicer, sportier package. And it also got 30 m.p.g. in a Driver's Seat test, although reliability is an unknown (new model, new factory, old Volkswagen issues). For people who need lots of room inside and like economy, the TDI diesel Passat may be an even better way there.